Climate Change Characteristics And Its Influence On Hydrology And Water Quality In Wuliangsuhai Basin In Recent 50 Years

Wuliangsuhai is in the north of China,Located in Bayannaoer City,is a lake formed by the diversion of the Yellow River.In recent years,with the continuous development of social economy,city urbanization,Hetao area of Bayannaoer city water consumption increased,resulting into Wuliangsuhai volume decreased.And a large number of life,industrial sewage into the Wuliangsuhai,making the lake water pollution is serious,the contradiction between water supply and demand increased.This article is based on the Wuliangsuhai Lake Basin in recent 51 years of meteorological data(rainfall,evaporation,temperature)and Wuliangsuhai 24 years over the same period of hydrology(The inflow,outflow water and the water level and capacity),water quality data(5,7,10 months).By comparing the trend of 1961-2011 meteorological data in Wuliangsuhai watershed and the Wuliangsuhai hydrology and water quality data during 1988-2011 years,we draw the following conclusions:(1)Wuliangsuhai watershed rainfall over the years show a rising trend,but not obvious,and the most significant trend is summer;Spatial distribution is not uniform,from east to west gradually decreasing;Main change period is 6-8 years;No obvious change year.(2)Significant growth in Wuliangsuhai watershed to the temperature for many years,consistent with the global warming background,and winter rise the most obvious,continue signs of warm winter;Temperature spatial distribution is uneven,from the north to the South and from the east to the west gradually increasing.Cycle is mainly dominated by 60 years or so.The temperature begin to change in 1991.(3)For many years the evaporation of Wuliangsuhai watershed show the first increase and then decreased,reach a peak in 80 s.The four seasons change is consistent with the change of the year.Spatial distribution is uneven,from the north to the South and from east to west gradually increased;The long cycle as the main change cycle;Evaporation begin to change in 2003.(4)Both the inflow and outflow water show obvious downward trend.The water level height and the capacity of the reservoir are on the rise,and the change period is about 13 a.Mutation years are in 2000,2008,2004.All the water quality indexes of Wuliangsuhai Lake,Except the dissolved oxygen and PH,all indicators show a downward trend,the overall water quality is worse than V.(5)Influence of the rainfall for hydrological factors are not significant,and the change of water in Wuliangsuhai delayed rainfall.The height of the water level,the storage capacity and temperature showed a significant positive correlation,especially during the summer temperature changes.Temperature and effluent show significant negative correlation,but temperature and inflow is not obvious.Rising temperatures have intensified Wuliangsuhai overall water quality,and the influence degree is bigger.The evaporation of Wuliangsuhai Lake Basin shows a significant negative correlation for water level elevation and storage capacity.And the spring,summer are the most obvious season.Evaporation is not obvious to the impact of water inflow and discharge.With the change of annual evaporation,the dissolved oxygen content in water reduced and the content of harmful substances increased,which aggravated the deterioration of the water body.(6)The main factors influencing the capacity are runoff,evaporation and temperature,the discharge flow as artificial regulation is the main factor influencing the capacity change.At the entrance,the water pollution is mainly caused by COD,ammonia nitrogen;The center of the lake,the pollution is mainly caused by ammonia nitrogen,total phosphorus and BOD;Export is mainly caused by BOD,COD,total nitrogen,total phosphorus.